Atypical lexical/semantic processing in high-functioning autism spectrum disorders without early language delay.

Although autism is associated with impaired language functions, the nature of semantic processing in high-functioning pervasive developmental disorders (HFPDD) without a history of early language delay has been debated. In this study, we aimed to examine whether the automatic lexical/semantic aspect of language is impaired or intact in these population. Eleven individuals with Asperger's Disorder (AS) or HFPDD-Not Otherwise Specified (NOS) and age-, IQ-, and gender-matched typically developing individuals performed a semantic decision task in four conditions using an indirect priming paradigm. Semantic priming effects were found for near-semantically related word pairs in the controls, whereas this was not the case in the AS or HFPDDNOS participants. This finding suggests similarities in the underlying semantic processing of language across PDD subtypes.